leases have their perks. if you drive 70 miles a day back and forth from work, then no, probably not a good idea. but if youre a college kid or someone with a small budget that wants an affordable, reliable car, theyre great if you get something that fits. would i lease a benz? no. but I have a 2011 Nissan sentra that i got for no down payment with the title tax and acquisition waved, and i pay 110 a month. Coming from an old pickup, between gas and repairs im saving a silly amount of money.i also dont have any headaches if i were to break down, or something failed, because it is all covered under warranty. theres definitely people that can use a lease to their benefit, like me.
but to answer the OPs question, its probably not worth sinking money into a car that isnt technically yours, youre really just renting it for an extended period of time. and if you decide to do anything to it, keep all the stock parts because you have to return the car the way you took it off the lot.